Astro Sfa 105 Ch 13

Front 1

What do low-mass stars like the Sun leave behind when they die?

Back 1

White dwarfs

Front 2

What do high-mass stars leave behind when they die?

Back 2

Supernovae, leaving behind neutron stars and black holes

Front 3

What is the term for what is essentially the exposed core of a star that has died and shed its outer layers in a planetary nebula?

Back 3

White dwarf

Front 4

Compared to the Sun, are white dwarfs brighter or dimmer?

Back 4

Dimmer

Front 5

From what source is the degeneracy pressure found in white dwarfs?

Back 5

Closely packed electrons

Front 6

What is the term for the degeneracy pressure created by closely packed electrons?

Back 6

Electron degeneracy pressure

Front 7

What is likely to be the leftover product of our Sun?

Back 7

Carbon

Front 8

T or F
More massive white dwarfs are actually smaller insize than less massive one.

Back 8

True

Front 9

Why is the more massive white dwarf smaller?

Back 9

Because its gravity can compress its matter to a much greater density

Front 10

Describe the quantum mechanics that govern the sizes of white dwarfs?

Back 10

The electrons respond to the compression arising from greater gravity by traveling faster.

Front 11

What happens to degeneracy pressure strength as the white dwarf compresses?

Back 11

It becomes strong enough to resist the greater force of gravity.

Front 12

T or F
The most massive white dwarfs are the biggest.

Back 12

FALSE
The most massive white dwarfs are the smallest.

Front 13

In what size white dwarfs, more massive or less massive, are the elctron speeds higher?

Back 13

More massive

Front 14

What is the white dwarf limit?

Back 14

tHE FACT THAT NO WHITE DWARF CAN HAVE A MASS GREATER THAN

1.4M
Sun

Front 15

Why cannot a white dwarf have a mass larger than

1.4M
Sun?

Back 15

Neither electrons nor anything else can travel faster than the speed of light.

Front 16

What is the other name for the white dwarf limit?

Back 16

Chandrasekhar limit

Front 17

What are the 2 absolutes found in Einstein's theory of relativity?

Back 17

1. the laws of nature are the same for everyone
2. The speed of light is the same for everyone

Front 18

What stage does a cooled down white dwarf become?

Back 18

black dwarf

Front 19

What happens to a white dwarf in a close binary system?

Back 19

It can gain mass as mass spills from its companion

Front 20

What is the term for the process of infalling matter that forms the whirlpool-like disk around a white dwarf star in a binary ssytem?

Back 20

Accretion

Front 21

What is the term for the whirlpool-like disk formed by the infalling material from one star to a white dwarf in a binary system?

Back 21

Accretion disk

Front 22

What can provide a dead white dwarf with a new energy source?

Back 22

Accretion

Front 23

What is the term for the thermonuclear flash that results when a white dwarf blazes back to life as its hydrogen layer burns after it has accreted gas from its companion star in a binary system?

Back 23

Nova

Front 24

T or F
A nova is far more luminous than a supernova.

Back 24

False
A nova is far less luminous than a supernova.

Front 25

T or F
Accretion can resume after a nova explosion subsides, so that the entire process of accretion and nova can repeat itself.

Back 25

True

Front 26

What is the term for the material that is expanded outward from that was accreted onto the surface of a white dwarf?

Back 26

nova remnant

Front 27

What happens each time a nova occurs?

Back 27

The white dwarf ejects some of its mass.

Front 28

What happens when a white dwarf gains enough mass to approach
the white dwarf limit

white dwarf limit = 1.4M
Sun

Back 28

the white dwarf explodes completely in what is called a white dwarf supernova

Front 29

What is the term for the exploding white dwarf when it reaches the white dwarf limit?

Back 29

White dwarf supernova

Front 30

What element acts as the bomb that creates a white dwarf supernova?

Back 30

Carbon

Front 31

What is the term for the iron catastrophe that leads to a super nova ending the life of a high-mass star?

Back 31

Massive star supernova

Front 32

What is the term for the ball of neutron created by the collapse of the iron core in a massive star supernova?

Back 32

Neutron star

Front 33

What is essentially a neutron star/

Back 33

giant atomic nuclei made almost entirely of neutrons and held together by gravity

Front 34

What holds together the giant atomic nuclei of a neutron star?

Back 34

Gravity

Front 35

In a neutron star, what particles are closely packed?

Back 35

Neutrons

Front 36

What supports the neutron nuclei against the crush of gravity?

Back 36

neutron degeneracy pressure

Front 37

Who first discovered neutron stars?

Back 37

Jocelyn Bell

Front 38

What is the term for rapidly pulsing radio sources?

Back 38

pulsars

Front 39

What is the term for the neutron stars left behind by the supernova explosions?

Back 39

pulsars

Front 40

What happens eventually to a pulsar's spin?

Back 40

It slows so much that they are no longer detectable

Front 41

T or f
All pulsars are neutron stars.

Back 41

True

Front 42

T or F
All neutron stars are pulsars.

Back 42

False,
NOT all neutron stars are pulsars

Front 43

What is the term for close binaries that contain accreting neutron stars?

Back 43

X ray binaries

Front 44

What is the termfor the bursts of energy that is generated when helium fuses rapidly to make carbon and heavier elements generating a burst of energy that flows from the neutron star in the form of X rays?

Back 44

X ray bursters

Front 45

What is the equivalence principle?

Back 45

The effects of gravity are exactly equivalent to the effects of acceleration.

Front 46

Who developed the equivalence principle

Back 46

Einstein

Front 47

What is the term for the seamless, four dimensional entity when we consider the 3 dimensions of space in addition to time?

Back 47

spacetime

Front 48

What is the term for the observed bending of light by distant galaxies?

Back 48

gravitational lensing

Front 49

How does a "black hole" gets its name?

Back 49

Nothing, not even light, can escape from a black hole

Front 50

Describe the escape velocity of a black hole?

Back 50

It is greater than the speed of light.

Front 51

According to Einstein, what does gravity arise from?

Back 51

curvature of spacetime

Front 52

T or F
Gravity gets weaker and weaker as we approach a black hole.

Back 52

FALSE<
Gravity gets stronger and stronger as we approach a black hole.

Front 53

What shape are black holes?

Back 53

spherical, not funnel like.
Funnel would indicate a 3 dimension

Front 54

What is the term for the boundary between the inside of the black hole and the universe?

Back 54

event horizon

Front 55

What marks the point of no return for objects entering a black hole?

Back 55

Event horizon

Front 56

How do we think of the size of a black hole?

Back 56

Based on its event horizon

Front 57

What is the term for the radii of the sphere that surrounds a black hole?

Back 57

Schwarzchild radius

Front 58

What does the size of a black hole's Schwarzchild radius depend upon?

Back 58

on its mass

Front 59

When does a stellar core become a black hole?

Back 59

When the core shrinks to a size smaller than its Schwarzschild radius

Front 60

T or F
The black hole still contains all the mass and has the gravity associated with the mass of the collapsed stellar core.

Back 60

True

Front 61

What is the term for infinitely tiny and dense point in the black hole's center?

Back 61

Singularity

Front 62

T or F
Time runs more slowly on the clock nearer to the black hole

Back 62

True

Front 63

T or F
Tidal forces near a black hole are trillions of times stronger that the tidal forces of the Moon on the Earth.

Back 63

True

Front 64

What is the most promising location of a black hole that we know of?

Back 64

An X-ray binary called CygnusX-1

Front 65

T or F
Some gamma ray bursts seem to come from the formation of black holes

Back 65

True

Front 66

Why are gamma ray photons so difficult to focus?

Back 66

Because they carry so much energy that they tend to penetrate through a telescope's mirror

Front 67

How did we confirm the origins of gamma ray bursts?

Back 67

When NASA launched the Compton Gamma Ray Observatory.

Front 68

What is another name for the Compton Gamma Ray Observatory?

Back 68

Compton

Front 69

What did the Compton discover about the source directions of gamma ray bursts?

Back 69

They are random coming from all directions in space

Front 70

T or F
Gamma ray bursts come from inside our galaxy.

Back 70

False,
Gamma RAy Bursts come far outside our galaxy

Front 71

What appear to be the most powerful bursts of energy that ever occur in the universe?

Back 71

Gamma Ray bursts

Front 72

Name the 2 types of gamma ray bursts:

Back 72

1. type associated with explosions of massive stars; and
2. type lasting only a few seconds

Front 73

What is thought to be the sources of gamma ray bursts?

Back 73

1. the collision of a binary system with 2 neutron stars or
2. the collision of a neutron star and a black hole